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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"
  1. GRB 180402A: RATIR Upper Limits
  2. GRB 180402A: LCO McDonald observations
  3. GRB 180402A: Swift detection of a possibly short burst
  4. GRB 180331B: Swift/UVOT Upper Limits
  5. GRB 180331B: Swift-XRT refined Analysis
  6. GRB 180331B: AbAO optical observations
  7. GRB 180331B: Swift-BAT refined analysis
  8. GRB 180331B: Enhanced Swift-XRT position
  9. GRB 180331A: Swift-BAT refined analysis
  10. GRB 180331B: Swift detection of a burst
  11. GRB 180331A: Swift-XRT refined Analysis
  12. GRB 180329B: LCO FTS observations
  13. GRB 180331A: Swift/UVOT Upper Limits
  14. GRB 180331A: Enhanced Swift-XRT position
  15. GRB 180331A: Swift detection of a burst
  16. GRB 180329B: VLT/X-shooter spectroscopic observations
  17. GRB 180329B: Swift-BAT refined analysis
  18. GRB 180329B: Swift/UVOT Detection
  19. GRB 180329B: RATIR Optical Observations
  20. Swift Trigger 819863 is not a GRB
  21. GRB 180329B: NOT optical afterglow detection
  22. GRB 180329A: Swift-BAT refined analysis
  23. GRB 180329B: Swift-XRT refined Analysis
  24. GRB 180329B: Enhanced Swift-XRT position
  25. GRB 180329B: Swift detection of a burst with an optical afterglow
  26. GRB180325A: AstroSat CZTI detection
  27. Swift Trigger 819301: possible GRB 180329A
  28. GRB 180325A: VLT/X-shooter spectroscopic observations
  29. Konus-Wind observation of GRB 180318A
  30. Konus-Wind observation of GRB 180326A
  31. Konus-Wind observation of GRB 180317A
  32. GRB 180325A: further NOT observations
  33. IPN Triangulation of GRB 180326A (long)
  34. GRB 180325A: Swift/UVOT Detection
  35. Konus-Wind observation of GRB 180316A
  36. Konus-Wind observation of GRB 180324A
  37. Konus-Wind observation of GRB 180325A
  38. GRB 180325A, Swift-BAT refined analysis
  39. GRB 180325A: GROND observations
  40. GRB 180325A: Global MASTER-Net OT prompt observations
  41. GRB 180325A: TAROT Calern observatory optical observations
  42. GRB 180325A: D50 early optical follow-up
  43. GRB 180325A: Swift-XRT refined Analysis
  44. GRB 180325A: Enhanced Swift-XRT position
  45. GRB 180325A: Optical Photometry with SLKT
  46. GRB 180325A: RATIR Optical Observations
  47. GRB 180325A: prompt REM optical/NIR detection
  48. GRB 180325A: NOT redshift
  49. GRB 180325A: prompt LT observations
  50. GRB 180324A, Swift-BAT refined analysis
  51. GRB 180325A: Swift detection of a burst with an optical counterpart
  52. GRB 180324A: Swift/UVOT Upper Limits
  53. GRB 180324A: Swift-XRT refined Analysis
  54. GRB 180324A: Enhanced Swift-XRT position
  55. GRB 180324A: RATIR Optical Observations and Possible Afterglow Detection
  56. GRB 180324A: KAIT Optical Upper Limit
  57. GRB 180324A: Prompt enhanced Swift-XRT position
  58. GRB 180324A: Swift detection of a burst
  59. IBAS Alert n. 8033: Not a GRB
  60. IPN Triangulation of GRB 180318A (long)
  61. IPN Triangulation of GRB 180317A (short/hard)
  62. IBAS Alert n. 8032: Not a GRB
  63. GRB 180316A: RATIR Optical Observations
  64. GRB 180316A: MITSuME Akeno optical upper limits
  65. GRB 180316A: MITSuME Okayama optical upper limits
  66. GRB 180316A: TSHAO optical observations
  67. GRB 180314A: AstroSat CZTI detection
  68. GRB 180316A: RATIR Optical Observations, Possible Re-brightening
  69. Konus-Wind observation of GRB 180314A
  70. GRB 180316A: Swift-BAT refined analysis
  71. GRB 180316A: Swift-XRT refined Analysis
  72. GRB 180316A: Swift/UVOT Detection
  73. GRB 180316A: RATIR Optical Observations
  74. GRB 180316A: Enhanced Swift-XRT position
  75. GRB 180316A: LCO Cerro Tololo observations
  76. GRB 180314A: MITSuME Okayama optical upper limits
  77. GROND observations of GRB 180316A
  78. GRB180316A: MASTER-IAC OT light curve
  79. GRB180316A: MASTER-IAC optical detection
  80. GRB 180316A: Prompt enhanced Swift-XRT position
  81. GRB 180316A: Swift detection of a burst
  82. GRB 180314B: RATIR Optical Observations
  83. GRB 180314B: Swift-BAT refined analysis
  84. GRB 180314B: Zeiss-1000/CrAO optical upper limit
  85. GRB 180314B: Swift/UVOT Upper Limits
  86. GRB 180314B: Swift-XRT refined Analysis
  87. GRB 180314B: Enhanced Swift-XRT position
  88. GRB 180313A: Fermi GBM detection
  89. GRB 180314B: Prompt enhanced Swift-XRT position
  90. GRB 180314B: Swift detection of a burst
  91. GRB 180314A: Swift-BAT refined analysis
  92. Swift Trigger on MAXI J1820+070
  93. GRB 180314A: TAROT La Silla observatory optical observations
  94. GRB 180314A: LCO Siding Springs observations
  95. GRB 180314A: Swift-XRT refined Analysis
  96. GRB 180314A: Fermi GBM observation
  97. GRB 180314A: VLT/X-shooter redshift
  98. GRB 180314A: Swift/UVOT Detection
  99. GRB 180314A: REM optical/NIR observations
  100. GRB 180314A: MASTER-Net OT dtetction

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